Actual lens positions of three intraocular lenses in highly myopic eyes: an ultrasound biomicroscopy-based study

Aim To evaluate the actual lens positions (ALPs) of three intraocular lenses (IOLs) in highly myopic eyes and to identify relevant factors using ultrasound biomicroscopy (UBM). Methods Ninety-three highly myopic eyes (93 patients) that underwent uneventful cataract surgery were included: 36 eyes were implanted with Zeiss 409MP IOLs, 27 with Rayner 920H IOLs and 30 with HumanOptics MCX11 IOLs. The prediction error (PE), ALP determined by UBM and the factors associated with ALP at 3 months after surgery were evaluated. Results The eyes in the MCX11 IOL group had a more hyperopic PE (0.67±0.45 diopters (D)) and greater ALP (4.86±0.39 mm) than those in the 409MP and 920H IOL groups at 3 months after surgery (PE: −0.25±0.54 and −0.16±0.65 D, respectively; ALP: 4.34±0.26 and 4.14±0.32 mm, respectively). The MCX11 IOLs showed more backward bending deformation after surgery than 409MP and 920H IOLs. The radius of curvature of the IOL was negatively correlated with ALP (r=−0.532, p=0.002) in the MCX11 IOL group, but not in the other two groups. Multivariate analysis showed that MCX11 IOLs were more prone to bending in highly myopic eyes with a smaller anterior capsular opening (β=0.236, p=0.023) and lower implanted power (β=0.542, p=0.001). Conclusion In highly myopic eyes, IOLs with good capsular support show less backward bending, which result in a more stable lens position and refractive status postoperatively. Severe capsular contraction and low implanted power are risk factors for bending of certain IOLs.